Air vehicles, such as commercial and military jet aircraft, typically use one or more propulsion systems each powered by an engine, such as a gas turbine engine. The propulsion system may include a nacelle that houses the engine, and the nacelle may include a fan cowl that forms an outer portion of the nacelle and that surrounds an engine fan. The fan cowl typically includes two portions or halves that may be latched together and unlatched, via one or more latch assemblies located at the bottom or lower portion of the fan cowl. The fan cowl portions or halves may be unlatched to gain access to the fan cowl, for example, to perform maintenance, service, and/or inspection operations of the fan cowl and/or engine, while the air vehicle is grounded.
However, the location of such latch assemblies may make it difficult to notice, upon a quick visual inspection, whether the fan cowl is in a latched condition or in an unlatched condition. If the latch assemblies are not properly latched or secured prior to engine operation and flight, the fan cowl halves may separate and detach from the nacelle during flight.
Known systems and methods exist to indicate a latched condition or an unlatched condition of the latch assemblies on known fan cowls. However, such known systems and methods may suffer from various disadvantages or insufficiencies.
For example, one known indication system and method involves the use of electronic components, such as sensors, installed at or in the fan cowl that are wired to the flight deck to provide an indication or signal in the flight deck equipment regarding a latched condition or an unlatched condition of the latch assemblies. However, such known indication system and method does not provide a real-time indication during maintenance, service, and/or inspection operations, and may require personnel performing such operations to access the flight deck to retrieve the information regarding the indication status. Moreover, such known indication system and method may require electrical power to operate, and thus, the aircraft power must be operational and turned on to find out the information regarding the indication status. However, the aircraft power may not typically be turned on by the pilot until hours after a mechanic or service operator has performed the maintenance, service, and/or inspection operations. In addition, such known indication system and method having sensors and wiring may have reliability issues after being exposed to a high heat and high vibration environment in the fan cowl and engine during flight. Further, such known indication system and method may require additional electronics that may impact multiple computing systems in the aircraft, and may affect flight crew procedures and workload.
Another known indication system and method uses the latch of the latch assembly itself as visual indication by manually attaching a colored flag to the latch of the latch assembly during maintenance, service, and/or inspection operations. However, the size and position of the latches of the latch assemblies, when unlatched, may not be prominent enough to ensure that such colored flag would be noticed during the maintenance, service, and/or inspection operations, for example, a flight crew walk around inspection. Moreover, at least one regulatory agency, for example, the European Aviation Safety Agency (EASA), has deemed such known indication system and method, alone, insufficient for certain aircraft models.
Accordingly, what is needed is a system and method for a latch indication system for an engine fan cowl of an air vehicle that provides enhanced visualization and detection, in real-time, of the latched condition or unlatched condition of one or more latch assemblies on the engine fan cowl, that is easily retrofittable on existing air vehicles, that is simple to use and reliable, and that provides advantages over known systems and methods.